Process of and apparatus for decomposing potassium-bearing minerals



jan, 6,

g C. M. ALEXNDER PROCESS 0F AND APPARATUS RoR DEcoMPosING PoTAssIUM BEARING MINERALS Filed Sept. 9, 1920 E g1/Wenko@ C@ w. www@ lio others skilled, in the art to which it apperu memes Jan. e, 192s.

UNITE "CLWE MOlRRIS ALEXANDER, OF WAXAHACHIE, TEXAS.

PBVLDCIESS OFv AND APPARATUS FOR DECOMPOSING POTASSIUM-BEARING kMNERMLLS.

Application aies september e, ieee. serial No. 409,097.

To all 'whom t may concern.'

Be it known that I, CLIvE M. ALEXANDER, a citizen ofthe United States, residing at Waxahachie, in the county of Ellis, State ot Texas, have invented certain new and useful Improvements lin Processes of and Appa- `ratus for Decomposingv Potassium-Bearing reactionchamber wherein the Minerals; and. I do hereby declare the folllowing to be a full, clear, and exact description of the invention, such as will enable tainsto make and use the same.

This lnventlon relates to processes ot and apparatus for decomposing potassium bear- 1.5

Imaking potash throughthermally decomposing 'p mg minerals, and .it comprises a method ot' otassium compounds by causing combustion of heat generating materials in intimate contact with the potassium bearing compound, accomplished byinjectmg a mixture of ypulverized solids and gases into a heat necessary potassium commixture is ob l tained through the. combustion of fuel which i's also a part of said mixture. The invention also comprises a combination of apparatus elements including a reaction chamber land means for mixing and injecting the reaction materials and heating` materials therein. t..

for the decomposition of the .After the-materials have reacted to a certain point, I nd itI advantageous to inject steam into contact with the mixture, which tends to freeze the reaction and prevents it running in the reverse direction, thus giving a better potash recovery. The injection of steam is made just after the materials leave the high temperature zone.

Potassium compounds have many uses in the arts. and are especially valuable as fertilizer ingredients. Many methods have been used inthe industry for obtaining potash in a form for utilization as a fertilizer but have not proved very successful in an economic way. Among the sources of'potash other than.' the directly usable' natural deposits I might be mentioned kelp, and mineral depos1ts, such as alunite y and ieldspars; it is .also obtained as a by-product from cement 'kilns and blast furnaces.

The greatest possible source ol' potassium is the silicate minerals from which many attempts have been made to recover it through extraction by lixiviation with chemicals or. through thern ing. These methods are mal decomposition, alone or with the aid of chemicals. These processes have not been economical on account of the inefliciency of reaction, cost of materials, and operating cost, largely due to wear and tear onthe apparatus. i

Many processeshave been devised whereby the linexpensive potassium bearing silicates are heated to their decomposition temperatures and the potassium then fixed through the action ofsome chemical agent or are heated to a. temperature whereby the potash is volatilized. It is almost impossible to build an apparatus to withstand the highr temperature necessary for decomposition when the heat is applied from the outside. For this reason in processes using high temperatures the heat is applied direct either by blowing air into a retort containing llumps of the mineraljand coke, or by electrical heatexpensive and do not attain eiiicient decomposition of the mineral or fixing of the potassium even though chemicals are used therewith.

In the present invention I intimately mix u the mineral to be decomposed and the heat producing materials before introducing them into the reaction chamber and inject these by suitable means into this chamber. All thesolids are finely pulverized and Asuspended in the gases. The heat necessary to maintain the reaction temperature is obtained through the combustion of the fuel and air inthe same .zone and in intimate contact with the mineral to be decomposed. Very eiiicient heating` is thereby obtained and the temperature and degree of combustion can be readily controlled. Since the heating' is effected within the reaction chamber instantaneous heat .transfer to the heat absorbing material is obtained and also the reaction chamber is not subjected to as high V.a temperature as would be the case where heating ism accomplished from the outside. The reaction chamber can further be made gas tight'and 100' also can be cooled on the outside 'by using a cooling jacket with air or water. 'The 1njection of the heating agents with the min l eral to be' decomposed has another essential functiom that of carrying the pulveri'zed 105 solids in suspension. Withthe solidspulverized and suspended in the gases the maximum amount of surface is thereby exposed to heating and to reaction. 'I hepresult is a very complete decompositionrofthe potassium hearing mineral and fixation of the.

potassium in a utilizable form.

ln carrying out this process the potassium bearing silicate, such as potash feldspar (orthoclase) KAISLO, slate. etc.. and tln` fuel, coal or coke, are first dried to remove I r'loisturc. The tu'o materialsare mixed inapproximately equal.proportions and then pul Verized to 95% through l0() mesh and 85% through 200 mesh which gives an average mix of approximately l5() mesh. This highly pulverized mixture of reacting; mate'A 'rials an'd fuel is conveyed to a mixing device or tuyrc wherein it is intimately mixed with the desired proportion of air and continuousl blown into the reaction chamber. Approxlmately 150 cubic feet ol' air are 'required :for the complete combustion of. :1 pound of coal or coke. This air, when 1njected through the tuyerc, has a carrying ca-l pacity for approximately three pounds of pulverized solids, i. e., under conditions Where the combustion of a pound of coal is sufficient to "maintain the temperature re-` quired, two pounds of piilverized mineral Acanbe carried in addition by the air. lith more air proportionately more solids can be carried suspended in the gases. However. it has been found that the amount of mineral i that can be added is less than .the maximum carrying capacity of the air since it smothers the fuel combustion and prevents ignition Prior to injecting the material to hc decomposed it is necessary. through the usc-of fuel and air alone, to heat the reaction chamher to the decomposition temperatru'e, which is approximately 250()o F. This temperature once attained is maintained through inject- 'lll ing they fuel inthe required quantities along With the mineral to he decomposed. Combustion takes place in intin'iate contact with the material to be decomposed vand results yin a most efficient' heat transfer. 0n account of the veryfinely divided state of the solids, the-y expose maximum surface fol-'reaction and act much like gases. Decomposition of the potassium bearing' mincral takes place readily at the high temperature and the po tassium compounds set free are held fixed in the combustion gases through the reduced' pressure efl'ect and combines with the carbon dioxide. The potash is carriled from the reaction chamber in the combustion gasesv and is later on collected hy condensing as potassium carbonate The operatingr conditions are Very 'readily maintained and the reaction most e c-iently'controlled and carried out ,in ,what may be termed the vapor state, since the solids are suspended and so finely divided that they-act Avery much like a true vapor.

When coke. is used as the fuel it is hest'to add a little producer gas with the reaction mixture in order to obtain uniform ignition throughout the mass. With coals containing; A10% or more volatile matter this is not necessary. Producer ,gas alone can also be readily used as the fueL ln order to more fully explain the invcntion, reference is made to the accompanying drawing, which illustrates in a diagram,-

matic Way an apparatus for Caimying out gas from the piodiiceigas linelI-l mayalso be arranged to be led into the tuyere.

The tuycre opens at its outer end linto a combustion and reaction chamber 14, lined With a suitable refractory material l5. .A

cooling' jacket 17 may be put around this' chamber, the inlet and outlet pipcsfor the reeling' water heiner indicated at l8 and 19. respectively. A suitable opening Q0 maybe provided for cleaning out the chamber '14'.

Steam injecting means, such as a .nozzle 22, to which steam yis'lead from thc strani line 23, may bc arranged to inject steam into the reacting.,y materials after the reaction has "proceeded to the desired point. 'l`his'steani cools the reacting materials and operates.. to freeze the reaction and to prevent itr The running in the opposite direction. steam injecting" means mayfconveniently be arranged at th` outlet from the chamber l4-. although itv should he understood lthat'it may be positioned further in or further out. in accordance with the particular conditions and tcn'iperatures that may be met with.

An outlet pipe 2l leads certain of thi` reaction products to one or more condenser-s 24. l

. lhe high ten'iperature attained yWithin the combustion and reaction chamber very rapidly and completely decomposesy the potassium containing mineral, resulting: principally in the formation of'potassium carbonate, alumina and aluminum silicate.

The potassium carbonate is more: volatile than the other products and passesl into the condensers, While the less volatile'products remain in the chamber 14. v

, The-degree of oxidation andthe temperature attained in the reaction chamber may be controlled both by regulating the amount of pulve'rized solid fuel and by the use offmore or less producer eas. Ordinarily with pnlverized coal, it will not be necessary to use the producer gas, butk with coke, it is preferable to use a small amount of suchgae in order to give better combustion and ignition in the chamber le.

l claim as my invention l. The process of decomposing potassium The ier)4 bearing minerals, comprising injecting pulverizerl mineral, fuel and air, into a combustion and reaction chamber. E

2. The process of decomposingl potassium bearing,r minerals, comprisiugmixing puli'erized mineral and fuel and blowing;l the mixture into a combustion and reaction chamber with a blast of air.

3. The process of decomposuugr potassium bearing minerals, eoniprising injectingr puliei'ized mineral, pulverized fuel, air and producer gas, into a combustion and reaction chamber.

4. The process of decomposing; pot; :sium bearing lr minerals, comprisinginjecting pulverized mineral. pulverized fuel and air, into a combustion and reaction chamber and after the reaction has proceeded 1o a certain point,'injectingsteam to freeze the reaction.

5. The process of forming potassium carbonate. comprising injecting pulverized potassiferous mineral and finely-divided cal"- bonaceous fuel by means of a blast ,of air, into a combustion and reaction chamber.

6. The process of decomposing potasl1- bearing minerals, comprising injectingr finely-dividcd mineral into a combustum and reaction chamber where it comes into in t-imatc Contact with burning fuel.

7. In an apparatus for decomposing min- -erals, a combustion and reaction chamber,

means for injecting fuel, the mineral being ti-cated, m nely dlvided form, and air, into sald chamber, and means, near ythe outlet ofAv the chamber, for injecting steam'.y

8, In an apparatus for decomposing ininerals, a combustion and reaction chamber, means for injecting a blast of air and fuel into the chamber and means for mingling the mineral being' treated in liely divided form with the blast before it enters the chamber.

S). 'Ihe process of treating a potassium almuinmn silicate for the formation of potassium carbonate, alumina and` aluminum silicate, comprising pulverizing the potassium aluminum silicate, mixing it with finely divided fue] and injecting the mixture, by means of a gas blast, into a. combustion and reaction chamber. i

10. process of treating a potassium aluminum silicate, such as .orthoclase or a potash feldspar, for the formation of potassium carbonate, alumina and aluminum silicate, in which the mineral is pulverized and injected by means of av gas blast, into a combustion and reaction chamber, where it comes. into intimate Contact with burningv fuel.

In' testimony whereof I aiiix my signature. y l

OLIVE MORRIS ALEXANDER, 

